Garden refuse shredding apparatus

ABSTRACT

This invention provides garden refuse shredding apparatus ( 10 ) which has a chipping rotor ( 20 ) supported for rotation about a vertical shaft ( 31 ) in a chamber ( 11 ) which has a hopper ( 14 ) which feeds refuse to radially disposed elongate chipper blades ( 30 ) which span a major part of the rotor ( 28 ). Fan blades ( 44 ) are supported on the rotor for creating an airflow through the hopper ( 14 ) to assist feed to the chipping rotor and to assist discharge of shredded refuse from the outlet ( 45 ). The chipping rotor ( 20 ) is driven directly from the vertical output shaft ( 36 ) of an electric motor or a petrol engine ( 21 ).

This application is a Division of U.S. application Ser. No. 09/786,494,filed Jun. 26, 2001, now U.S. Pat. No. 6,910,648, which is a 371 ofPCT/AV99/00727 filed Sep. 3, 1999.

TECHNICAL FIELD

This invention relates to garden refuse shredding apparatus suitable forshredding leaves twigs palm fronds and small branches.

BACKGROUND ART

Many types of garden refuse shredders are currently available andtypically they include an inlet hopper which can be loaded with gardenrefuse for shredding as well as a small bore inlet tube for introducingsmall branches to be shredded. Mostly these machines utilise a flailassembly at the base of the hopper for shredding material fed throughthe hopper and a separate chipper assembly at the base of the small boreinlet tube for chipping small branches introduced therethrough.

Disadvantages associated with these types of shredders stems from theirrelative complexity often making servicing, such as drive belt and bladesharpening operations, difficult and unreliable. Furthermore the flailassembly is often readily accessible from the underside of the machinemaking them dangerous for operation around children. In addition theflail assembly shreds green leafy material to a very fine form which maynot be the most suitable for garden mulching operations

Attempts have also been made to provide garden refuse shreddingapparatus based on a simple shredding rotor such as is used in domesticrotary mowers. However because of the nature of materials which are fedto such apparatus such as long fibrous articles including palm fronds,long grass and tree refuse, it is common for the material to becomeentangled about the drive shaft of the spinning rotor. This entanglementcan build up to such extent that it jams the machine and preventsfurther operation thereof or substantially reduces the efficiency ofoperation of the processor.

In some instances such entanglement about a drive shaft can damage sealsand the like which extend about that drive shaft. Any build-up of suchrefuse is also undesirable as it will impede the throughput of refuseand cause fouling about the drive shaft.

Garden refuse shredders and other driven garden appliances are oftenoperated by stand-alone petrol engines and electric motors fed by apower cord from the mains. Mains fed electric motors may be switched onand off remotely from the implement without knowledge of the user. Thiscan lead to dangerous operating conditions as when operated many suchelectrical implements operate relatively silently. Inadvertent contactwith a active parts of the implement may result with consequent injuryto a user. This is particularly so in the case of garden refuseshredders where operators may wear ear muffs and where the spinningchipper rotor if contacted may cause instant serious injury.

While it is possible to provide override switches and the like tominimise such accidental occurrences, it is difficult to shield againstcareless operating practices while maintaining simplicity andreliability of the apparatus.

Aspects of the present invention aim to alleviate one or more of theabove disadvantages and/or to provide garden refuse shredding apparatuswhich will be reliable and efficient in use.

DISCLOSURE OF INVENTION

With the foregoing in view, this invention in one aspect resides broadlyin garden refuse shredding apparatus including:—

a chamber having a refuse inlet and an outlet for shredded material;

fan means for creating an outflow of air from said outlet

a shredding rotor supported for rotation in the chamber;

at least one elongate chipper blade fixed for rotation with the rotorand extending inward from adjacent the outer periphery of the rotor:

a respective aperture through the rotor in front of the or each chipperblade through which material shredded by the chipper blade may pass;

a feed hopper for directing refuse through the refuse inlet into thechamber in the path of the chipper blade or blades, and drive means forrotating the rotor.

Suitably the fan means are supported on the rotor and induce an air flowthrough the feed hopper so as to assist in induction of materialintroduced to the feed hopper into the housing and each elongate chipperblade extends inward from adjacent the outer periphery of the rotorsubstantially to or beyond the half radius position of the rotor.

Alternatively an air flow may be induced by an exhaust fan associatedwith the outlet from the chamber and air may be introduced eitherthrough the hopper or elsewhere. The induction may be such as to causethe feed of refuse from a storage into the chamber or the feed hoppermay feed gravationally into the chamber and the air flow may be used toassist induction of the refuse into the chamber.

The shredder may include a pipe inlet through which branches and thelike are fed to the shredding rotor which is suitably in the form of aheavy rotor having one or more relatively long chipper blades mountedthereon adjacent a complementary aperture through the rotor.

The or each chipper blade suitably has an outer portion which passesacross the pipe inlet and the outer portion of the inlet, while theinner portion of the chipper blades passe only across the inner portionof the inlet. For example the inlet is suitably particular and extendsacross about between one-half and three-quarter of the rotor's radialextent, while the pipe inlet extends across about the outer one-quarterto one-half of the rotor's radial extent. More suitably the inletextends across two-thirds of the rotor's radial extent, while the pipeinlet extends across one-third of the rotor's radial extent.

In one desired form which utilises gravity feed of refuse to thechamber, the teed hopper extends upwardly from an upper end wall of achamber in which a shredding rotor is supported for rotation about anupstanding axis and fan blades are mounted on the shredding rotor at theside thereof remote from the feed hopper, the fan blades forming the fanmeans.

The shredding rotor may be supported for rotation about a horizontalaxis or an inclined axis. It is preferred that the shredding rotor bemounted for direct drive from the output shaft of the drive motor whichmay be an electric motor or an internal combustion engine. In the caseof an internal combustion engine it is preferred that the shreddingrotor be fixed to a hub which rotates with the output shaft of themotor. Suitably the hub extends about the output shaft and is supportedby a bearing mounted to an end wall of the chamber.

The chipper rotor and bearing may be supported on the lower end wall andbe connected to the motor such as by a splined or dog connection.Suitably however both the motor and the bearing for the hub are mountedto the upper end wall of the chamber containing the shredding rotor.Preferably the bearing is of the type which isolates end and radialloads applied by the shredding rotor from the engine. In this manner theouter end of the output shaft is supported by the hub bearing againstloads imposed by the rotor.

Preferably the hub bearing is a self-aligning bearing of the type whichmay be locked to the hub, such as a self-aligning cam-lock sealed ballbearing, which is locked to the hub after adjusting end play of theengine shaft so as to reduce end loads being transferred to thecrankshaft of the engine. For this purpose it is preferred that theengine is supported on a bracket above the hub bearing in such mannerthat access may be gained to the hub bearing for locking purposes aftersecuring of the rotor to the output shaft. This arrangement provides avery simple and cost effective means of achieving reliable operationwith direct drive from an internal combustion engine.

It is desirable that the shredding rotor be provided with means toprevent stringy material from becoming entangled about the hub of therotor. In one form this includes the provision of macerator blocks orblades mounted on the rotor and co-acting with complementary fixedblocks or blades mounted on the end wall of the rotor housing.

In a particular embodiment of the invention the shredding rotor isenclosed for rotation within a two part housing and is supported forrotation from a nominally horizontal upper end wall of an upper housingportion which also carries the motor and the hopper and which is hingedto a lower housing portion from which the upper housing portion may bepivoted to an open position to expose the shredding rotor. In this formthe lower housing part is suitably supported on skids or wheels.

This configuration of the rotor housing also constitutes another aspectof this invention and may be utilised to advantage without being limitedto utilising the particular shredding apparatus described above.

Similarly the configuration of the motor and rotor mounting utilising aseparate bearing to isolate the rotor loads from the direct mountedmotor shaft constitutes a further aspect of this invention and may beutilised to advantage without being limited to utilising the particularshredding apparatus or housing described above.

It is also preferred that in this form the upper housing parts beprovided with suspension means for suspending a catcher across an outletaperture in a side wall of the housing. Suitably the catcher is mountedremote from the hinging mechanism and preferably the outlet constitutesthe end of a volute shaped housing which provides an expanding path tothe outlet. It is also preferred in such arrangement that an induced airdraught by utilised to assist in feed through the feed hopper anddischarge of shredded material through the outlet.

In a further aspect this invention resides broadly in a method ofinhibiting entwinement of elongate articles about the drive shaft ofrotary processing members, the method including:—

forming a barrier wall about the drive shaft to substantially concealaccess between the walls from and to which the drive shaft extends tothe rotary processing member, and

providing complementary disrupting members on the respective walls fromand to which the drive shaft extends to the rotary processing member,the disrupting members comprising fixed and stationary members whichpass closely adjacent one another upon rotation of the rotary processingmember so as to disrupt material tending to pass to the drive shaft.

The disrupting members may be arranged between the drive shaft and thebarrier wall or at the side of the barrier wall which is remote from thedrive shaft. Suitably the access path across the barrier wall and pastthe disrupting members in a circuitous or labyrinth path.

The complementary disrupting members may be a plurality of substantiallyidentical complementary disrupting members arranged concentrically aboutthe drive shaft. Each of the complementary disrupting members may be apair of anvil members which rotate past one another such as a pair ofopposed pins or blades.

Suitably each of the complementary disrupting members includes a fixedanvil member such as a cylindrical projection and a blade member whichpasses closely adjacent exposed side and end faces of the cylindricalprojection. In one embodiment the or each cylindrical projection isconstituted by the cylindrical head of a high tensile cap screw or bolt.

The method of inhibiting entwinement of elongate articles about thedrive shaft of rotary processing member may also include providing airflow or pressure distribution arrangements about the drive shaft wherebymatter disrupted by the complementary disrupting members is induced toflow away from the drive shaft.

In another aspect this invention resides broadly in rotary processingapparatus of the type including a drive shaft extending from a fixedwall to an adjacent wall of a processing member driven for rotation bythe drive shaft, the rotary processing apparatus including:

a barrier wall mounted on one of said fixed or adjacent walls about thedrive shaft and terminating close to the other wall, and

complementary disrupting members extending from respective said fixedand adjacent walls so as to pass closely adjacent one another uponrotation of the adjacent wall relative to the fixed wall.

A plumber block or the like bearing is suitably mounted on top of ahorizontal fixed wall so as to support the rotary processing apparatusand cap screws, ie screws or bolts having cylindrical heads with asocket for receiving a key or the like, disposed equidistant from theaxis of the drive shaft pass upwardly through the fixed wall into thebase of the plumber block or the like and act as fixed disruptingmembers which cooperate with blades mounted on the adjacent wall.Suitably the blades have a horizontal part which terminates close to theouter ends of the cap screws and a vertical part which terminates closeto the side walls of the cap screws.

In yet a further aspect this invention resides broadly in a rotaryprocessor such as garden refuse shredder having a driven shaft driving ashredder mounted within a housing, an inlet to the housing for refuse tobe shredded and an outlet from the housing for discharging shreddedrefuse, wherein:

impeller means are associated with the shredder for inducing an inflowto the housing through the inlet and an outflow from the housing throughthe outlet. Suitably the housing provides an expanding travel path formaterial entering through the inlet and passing to the outlet and moresuitably this travel path is in the form of a volute or the like. Thedrive shaft may be driven by an electric motor or by an internalcombustion engine, in which case it is preferred that the shredder bemounted on the output shaft but supported by bearing means independentof the internal combustion engine. The drive shaft may be a horizontalshaft or a substantially vertical shaft. The shredder is suitably arelatively heavy disc supporting chipper blades thereon and havingapertures therethrough in front of the blades and through which shreddedrefuse may pass to be discharged.

In an electrically driven form of this invention in which the shreddingrotor is supported on the output shaft of an electric motor, theshredding rotor suitably includes a friction brake biased to an engagedattitude so as to cause the shredding rotor to slow quickly to a stoppedposition once electrical power to the driving motor has ceased and amanual on/off control associated with an onboard electrical switch whichcontrols the supply of electricity to the motor such that when thecontrol is moved to the on position for supplying electricity to themotor the brake is maintained in a disengaged position and when thecontrol is moved to the off position the brake is freed for stopping theshredding rotor.

Suitably the brake is a single shoe brake carried on a lever formovement to and from its engaged attitude and co-operable with a switchin its disengaged position to supply electricity to the motor. The brakeis suitably arranged as a leading shoe brake such that the effort tooperate the brake effectively is reduced.

The shredding rotor may also be supported within a shredder housingwhich is opened to provide service access to the shredding rotor andsuitably a latching arrangement is provided for holding the brake leveror other manual on/off control when in the on position in a blockingposition blocking the opening of the shredder housing.

The shredding rotor may be supported in a volute shaped housing and beprovided with wind vanes for creating an air flow therethrough from therefuse inlet to the outlet from the shredder housing.

A barrier wall may be provided about the output shaft of the motor as aguard against elongate fibrous articles becoming entwined about theshaft. Cutters mounted on the rotor of the shredding rotor and arrangedto pass across fixed anvils may be provided to disrupt fibrous articlesthat pass toward the output shaft also with a view to preventingelongate fibrous articles becoming entwined about the shaft and in afurther aspect of this invention the cutters are suitably in the form ofhardened plates extending upwardly through slots through the rotor topass close to the fixed anvils. Each plate may be welded to a mountingflange which is bolted to the underside of the rotor and preferably withbolts which trail the plate.

BRIEF DESCRIPTION OF DRAWINGS

In order that this invention may be more readily understood and put intopractical effect, reference will now be made to the accompanyingdrawings which illustrate a typical embodiment of the invention andwherein:—

FIG. 1 is a side view of the shredding apparatus fitted with a catcher:

FIG. 2 is corresponding view but shown without a catcher;

FIG. 3 illustrates the shredding apparatus disposed in a servicing mode;

FIG. 4 is a part-sectional view of the rotor and its mounting;

FIG. 5 is a cutaway plan view of the rotor assembly, and

FIGS. 6 and 7 illustrates in plan and side sectional views a furtherembodiment of the rotor assembly.

FIGS. 8 and 9 illustrates in plan and side sectional views a furtherembodiment of the rotor assembly and its mounting details;

FIG. 16 illustrates an electrically operated shredder in an operativemode;

FIG. 17 is a corresponding view but in an inoperative mode;

FIG. 18 illustrates the shredder in an open servicing mode;

FIG. 19 is a similar view to FIG. 3 but shown with the rotor removed;

FIG. 20 is a top view of the shredding rotor assembly, and

FIG. 21 is an underneath view of the brake assembly.

MODES FOR CARRYING OUT THE INVENTION

The garden refuse shredding apparatus 10 illustrated in the drawings hasa two-part housing 11 supported on rear wheels 12 and a front stand 13,a feed hopper assembly 14 and a small bore inlet tube 15 extendingupwardly from the upper housing part 16 and a catcher 17 suspended fromthe front of the housing 11.

The housing 11 contains a shredding rotor assembly 20, illustrated inFIG. 4, and supports a small petrol motor 21 thereabove for driving theshredding rotor assembly 20. Opposed pin hinges 22 attach the upperhousing part 16 to the lower housing part 19 at the rear thereof whichenable the upper housing part 16 and the components mounted thereon tofold to an open position as illustrated in FIG. 3, at which the handle24 rests on the ground and clear access is provided to the shreddingrotor assembly 20 through the open underside of the top housing part 16.The front of the top housing part 16 is retained on the lower housingpart 19, in use, by bolts 25.

As illustrated in FIGS. 4 and 5, the shredding rotor assembly 20 has adisc-like rotor 28 formed with opposed radially extending slots 27 atdiametrically opposite positions and a chipper blade 30 bolted to therotor 28 adjacent the trailing side of each slot 27.

Macerator blocks 29 are interposed between the blades 30 and are fixedto the rotor 28 with inner ends spaced from the hub 31 to which therotor 28 is bolted. Pins 32 extends down from the end wall 33 of theupper housing part 16 toward the rotor 28. The pins are positionedbetween the hub 31 and the macerator blocks 29.

The hub 31 is formed at the lower end of a thick-walled sleeve 35 whichis bored to accept the output shaft 36 of the motor 21 which is keyedthereto by a key in conventional manner. The lower end of the motorshaft 36 is threaded to receive a retaining bolt 37 which pulls therotor 28 against the end of the shaft 36. The rotor is also bolted tothe hub 31 by bolts 38.

The sleeve 35 is supported by a large capacity self-aligning cam-lockbearing 40 which is secured to the end wall 33 through a stiffening boss41. This bearing is locked to the motor shaft 36 so as to support theweight of and end thrust placed upon the rotor 28.

The bearing 40 also accommodates the side and impact loads imparted bythe operation of the chipper blades 30. This isolates undesirable loadsbeing applied to the crankshaft of the directly mounted motor 21 whichis supported on a channel shaped mounting 23 fixed to the end wall 33.The rotor 28 is relatively heavy and acts as a flywheel and in a typicalembodiment is formed from 5 mm thick steel plate.

The underside of the rotor 28 has impeller blades 44 bolted thereto soas to create an air flow through the open front 45 of the housing 11.This induces a downdraught through the feed hopper assembly 14 and thesmall bore inlet tube 15 which assists in feeding material to be mulchedtherethrough toward the rotor 28. A closure cap may be provided for thetube 15 to increase the draught through the hopper assembly 14.

The induced draught also carries shredded material through the outletwhich is normally closed by a flap 47 hinged along its upper edge andpivotable upwardly to permit a conventional grass catcher 50 to beremovably clipped to the housing 11 to receive the shredded material

It will be seen that the feed hopper assembly 14 has a forwardlyconvergent transition piece 51 extending from its underside to the inletaperture 52 formed in the top wall 33, while the inlet tube 15 is angledback to assist feeding of the material introduced therethrough.

In use when the rotor 28 is rotated at high speed, air is induced toflow through the feed hopper assembly 14 and inlet tube 15, which may becapped if desired. This air flow assists in the feeding of material tobe shredded to the rotor 28. Most of this matter will be shredded by thechipper blades 30 and pass through the apertures 27 for discharge to thecatcher.

Should refuse move across the top of the rotor 28 toward the hub 31 itwill be contacted by the macerator blocks 29 and be pulverised. The airdraft induced by the fan blades 44 will assist in discharging thepulverised material.

In the event that the chipper blades need servicing, they can beaccessed easily by releasing the bolts 25 and pivoting the top housingpart to its open position as illustrated in FIG. 3. In this position therotor 28 is stably supported for safe working conditions.

An inlet safety flap 48 is pivotally attached to the upper end of thehopper to close the hopper after the addition of material to beshredded. The flap 48 does not extend fully to the front wall 53 of thehopper 14 so as to provide an opening or air flow gap for maintenance ofa desirable air flow through the feed hopper 14 to assist with thefeeding and/or discharge process.

An alternate rotor 58 illustrated in FIGS. 6 and 7 carries opposedblades 56 formed with upturned inner ends 57 to provide cutters whichco-act with complementary arcuate blade 59 centred on the rotor axis andfixed to the end wall 55 of the upper housing part. The cutters 57 passclose to the blades 59 and cut up long strands of matter which may befed toward the boss 54. However the rotor arrangements of FIGS. 4 to 7are not particularly suited to coping with various types of refuse suchas palm frons for example. These are more efficiently coped with by theshredding rotor assembly illustrated in FIGS. 8 to 13 and describedbelow.

The preferred form of shredding rotor assembly 60 has opposed blades 61bolted to the rotor 69 and formed with upturned cutting or disruptingends 62 which are L-shaped to pass closely about the end face 63 andside face 64 of circular anvils 65 which in this embodiment areconstituted by Allen head bolts which bolt the end wall 66 to the robusthousing of the cam-lock nearing 67. The bolts 65 are high tensile boltswhich have relatively deep serrated cylindrical heads. With thisarrangement the close spacing between the L-shaped ends 62 with the sideand end faces of the bolts 65 will not vary with rotation of the bolts65.

An annular barrier wall 70 extends down from the end wall 66 toterminate closely adjacent the rotor 69. The barrier wall 70 closelyaccommodates the lower mounting flange 72 of the hub assembly 71 whichis carried by the cam-lock bearing 67. This hub is keyed to thedriveshaft 73 of the motor 74 and a central retaining bolt extendsthrough the rotor 69 into the driveshaft 73.

As can be clearly seen in FIG. 10, when the blades 61 are in line withone of the bolts 65 the only path thereacross to the hub assembly 71 isa circuitous or labyrinth path as indicated by the arrow 75, and beingfirst about the side and end face of the bolts 65 and then past thebarrier wall 70. This will provide an effective barrier against elongatefibrous articles entwining about the shaft. Material which travelsinward beyond the chipper blades 76 will be resisted by the barrier wall70 where it will be cut up or disrupted and then forced outwardly eitherby the motion of the rotor or the air flow across the rotor 69. Thethrough bolts for the chipper blades 76 also secure the impeller blades77 to the rotor 69.

FIG. 12 illustrates the simple and easy to manufacture nature of theshredding apparatus, being formed mostly of folded sheet metal boltedtogether and punched for bolt on mounting of the components such as themotor and bearing assembly, while FIG. 13 illustrates the ease ofservicing the working components which are normally concealed within therotor housing.

This arrangement provides a shredder of very simple form which has thebulk of its weight centralised between the wheels 12 and the stand 13for stable operation. The weight of the hopper is offset by the catcherand the handle 24 provides for simple balanced wheeling of the shredder10 from location to location and support for the opened housing.

As illustrated in FIG. 14, the inlet tube 80 is provided with a pivotedclosure flap 81 which normally falls down to a position at which itcloses the tube 80, thus assisting in maintaining a relatively high airflow through the inlet chute 14 to assist flow of refuse to the chipperblades. A coupling 82 at the end of a flexible hose 83 is provided withan external sealing ring 84 and it plugs into the upper end of the pipe80. The outer end of the hose 83 terminates in a suction nozzle andhandle assembly such as is illustrated diagrammatically at 85. Blockingmeans may also be provided for the partially open inlet chute to assistin creating a suitable vacuum effect at the nozzle 85.

In order to convert the shredder for use as a refuse blower, as shown inFIG. 15 a transition housing 90 is attached to the mountings 91 for thegrass catcher and converges to a tubular outlet pipe 92 to which aflexible hose 93 and nozzle assembly 94 may be connected. The nozzle 94is associated with a handle 95 for manipulation by a user. Thus the airdraft created by the fan blades can be used to advantage as aconcentrated stream for blowing surfaces clean of loose refuse.

The garden refuse shredder assembly 110 illustrated in FIGS. 16 to 21 ofthe drawings has a shredding rotor assembly 111, as illustrated in FIG.20 supported in a housing 112 and driven by an electric motor 113. Aninlet chute 114 is provided at the rear of the housing for entry ofgarden refuse and an outlet chute 115 is provided at the front of thehousing through which shredded material is discharged.

In this embodiment, the housing 112 is a two part housing having anupper part 120 pivotally connected by pivots 121 to a base part 122 suchthat the upper part 120 may be opened as shown in FIGS. 18 and 19 toprovide access to the shredding rotor assembly 111. Normally the housingparts are retained in their closed attitude by a pair of wing nuts whichbolt the upper part 120 to the base part 122.

Referring to FIG. 19 it will be seen that the shredding rotor assembly111 is contained within a volute shaped housing 124 formed with anexpanding discharge chute 125 extending to the outlet 115. FIG. 19 alsoillustrates the inlet 126 for refuse to be shredded and the anvil 127which is bolted to the trailing edge of the inlet 126 and which chipperblades 128 of the shredding rotor assembly 111 co-operate to shearrefuse fed through the inlet 126.

As shown in FIG. 18 the base part 122 is provided with an upstanding pin130 which passes through a complementary aperture 133 in the upperhousing portion 120 when the housing is closed. The upper end 131 of thepin 130 is then exposed above the upper housing 120 as illustrated inFIGS. 16 and 17.

The shredding rotor assembly 111 is provided with a mounting hub 135which receives the keyed output shaft of the electric motor 113. Theupper portion of the hub 135 extends upwardly above the housing 120 intoa cavity formed by an inverted channel shaped motor mounting bracket136. The motor mounting bracket supports a brake lever 137 which carriesa brake pad 138 and tension spring 139 which biases the brake pad 138into engagement with the upper portion of the hub 135.

The brake lever 137 extends forwardly through the front flange 140 ofthe motor bracket 136 and beyond the exposed upper end 131 of the pin130 which projects through the housing 120. An on/off switch 141 is alsocarried on the motor mounting bracket so as to cooperate with the brakelever such that when the brake lever is disengaged from the hub 135 andheld in the “ON” position, it will actuate the switch 141 to an onposition such that external electrical power supplied to the shredderwill be switched to the motor 113.

When the lever 137 returns to the engaged position, it releases from theswitch 141 which becomes open circuit so as to prevent supply ofelectricity to the motor 113. Once disengaged from an “ON” position, thebiasing of the lever 137 will urge the brake pad 138 into brakingcontact with the hub 135 to brake the rotor assembly 11 to a standstillin a relatively short space of time such as a matter of seconds.

The end 145 of the lever 137 which is exposed above the housing part 120forms an on/off control switch for the shredder and it is adapted to beretained in the “ON” position by engaging it with the exposed upper end131 of the pin 130. For this purpose, the upper end 131 of the pin 130is waisted at 150 and the end 145 of the lever is provided with akeyhole slot 151 whereby the end portion 145 may be captively engagedwith the upper end 131 of the pin 130 and held therein by its springbias.

When so engaged, the switch 141 is maintained closed and power issupplied to the motor 130. When the lever end 145 is released from thepin end 131, the spring 139 will pull the lever 137 to the brakingposition stopping power supply to the motor and at the same time brakingthe rotor to a standstill.

Should an operator want to gain access to the rotor assembly 111, theoperator may undo the wing nuts 142 with a view to pivoting the upperpart 120 of the housing 112 to the open position. This may be achievedprovided the on/off lever 137 is not engaged about the upper end of thepin 130. If it is so engaged and the electric motor is powered, thencaptive engagement of the lever end 145 with the pin end 131 willprevent the upper housing part 120 being pivoted to its open position.Thus the housing cannot be opened to gain access to the rotor assembly11 unless the lever 125 is in the off position.

Accordingly it will not be possible to gain access to the rotor assembly111 until the power supply to the motor 113 has been disrupted and therotor has been braked.

Referring to FIG. 21 it will be seen that the brake lever 137 isarranged with the pivot mounting at a leading position relative to therotation of the hub 135 such that the brake assembly is a leading shoebrake assembly which provides a self servo effect to assist actuation bythe tension spring 139.

It will also be seen from the drawings that the rotor assembly 111operates in the volute shaped housing and is provided with fan blades161 adjacent the apertures 162 in front of the chipper blades 128. Thefan blades induce a draft through the feed chute 114 and through theoutlet 115 to assist in through flow and discharge of shredded material.

It will be further seen that an annular barrier wall 163 is formedaround the output shaft 164 of the motor 113 so as to shroud the hub135. Fixed circular anvils which are preferably serrated and constitutedby the heads of Allen head bolts 165 are mounted adjacent the barrierwall 163 and complementary L-shaped cutting blades 166 extend throughslots 167 in the rotor 11. The blades 166 are welded to mounting plateswhich are bolted to the rotor 11 by trailing bolts 169. The L-shapedcutters 166 pass closely over the outside and lower end of the circularanvils 165 so as to cut up any fibrous material which may pass throughthe inlet 126 and move inwards above the rotor 11.

In the illustrated embodiment the outlet 115 is provided with adeflector 170 which deflects discharged material towards the ground. Thedeflector however may be pivoted to an inoperative position so as topermit a catcher to be engaged with the outlet to receive shreddedmaterial.

In operation the upper end of the inlet chute 114 is normally covered bya safety flap which does not prevent flow of air induced by the lowpressure created by the fan blade 161. Thus once operating, there is asignificant air flow induced in the inlet chute to assist feed ofmaterial to the cutter assembly and from the outlet to assist indischarge of shredded material.

As the material is fed through the inlet, it is engaged between theanvil 127 and a chipper blades 128 and chipped. It is then flungoutwardly and discharged with the aid of the induced draft. Thisoperation can only occur when the lever 145 is engaged about the pin 130as illustrated in FIG. 16. If the operator desires to service the rotor11, the upper part of the housing 120 cannot be opened until the lever145 has been freed from the pin 130 for movement to the brakingposition. Thereafter the wing nuts 142 can be released to enable thehousing parts to be opened. A further accessible master switch may beprovided if desired to provide an operator with a direct means ofswitching the power supplied to the shredder assembly 110 on or off.This may be accommodated on the handle of the shredder assembly 110 orplaced elsewhere as desired.

It will of course be realised that the above has been given by way ofillustrative embodiment of the invention, all such modifications andvariations thereto as would be apparent to persons skilled in the artare deemed to fall within the broad scope and ambit of the invention asis defined in he appended claims.

1. Garden refuse shredding apparatus including: a housing defining achamber having a refuse inlet for receiving refuse therethrough and adischarge outlet through which shredded material may be discharged; afeed hopper in communication with said refuse inlet for directing refusethrough said refuse inlet into said chamber; a rotor mounted in saidchamber to a vertical drive shaft or hub extending through a wall ofsaid housing, said rotor including a mounting plate connected to andadapted to rotate with said drive shaft or hub about its axis, and oneor more chipper blades integral with or mounted to said mounting platefor rotation therewith; and an internal combustion engine having anoutput shaft co-axial with and solidly connected to said drive shaft orhub for causing said rotor to rotate, said drive shaft or hub beingsupported in a bearing which is mounted to said wall through which saiddrive shaft or hub extends and said bearing is adapted to transfer axialworking loads from said drive shaft or hub to said housing.
 2. Gardenrefuse shredding apparatus according to claim 1, wherein said driveshaft or hub has a central bore and the output shaft of said engine isengaged in said central bore.
 3. Garden refuse shredding apparatusaccording to claim 2, wherein said drive shalt or hub is locked to saidoutput shaft by a key extending through the wall of said drive shaft orhub and engaging with a key way in said output shaft.
 4. Garden refuseshredding apparatus according to claim 3, wherein said key is secured bya collar extending about said drive shaft or hub.
 5. Garden refuseshredding apparatus according to claim 4, wherein said collar includesgrub screws which engage with said key.
 6. Garden refuse shreddingapparatus according to claim 1, wherein said bearing is outside saidchamber.
 7. Garden refuse shredding apparatus according to claim 6,wherein said bearing is a self-aligning bearing having an inner racewhich is locked to said drive shaft or hub for rotation therewith. 8.Garden refuse shredding apparatus according to claim 1, wherein saidbearing is a flange mounted cam lock bearing which is bolted to saidhousing wall and cam locked to said drive shaft or hub.
 9. Garden refuseshredding apparatus according to claim 1, including an engine mountingbase operatively connected to said housing and spaced from said housingwall to provide access to said bearing and wherein said internalcombustion engine is mounted on said base.
 10. Garden refuse shreddingapparatus according to claim 1, wherein said mounting plate is spacedfrom said wall and said drive shaft or hub between said wall and saidmounting plate is enclosed by a shroud extending about said drive shaftor hub.
 11. Garden refuse shredding apparatus according to claim 10,wherein said rotor includes one or more macerating means integral withor mounted to said mounting plate for rotation therewith adjacent saidshroud and adapted to macerate refuse fed into said chamber.
 12. Gardenrefuse shredding apparatus according to claim 1, including fan means influid communication with said chamber for creating an outflow of airthrough said outlet.
 13. Garden refuse shredding apparatus according toclaim 12, wherein said fan means are integral with or mounted to saidmounting plate for rotation therewith.